The invention relates to spherical particles comprising magnesium alcoholates or a mixture of magnesium alcoholates, a process for their preparation and their use.
It is known to prepare magnesium alcoholate. Thus, US 2001/0012908 describes the synthesis of magnesium alcoholates at a temperature of 30 to 60° C.
U.S. Pat. No. 5,556,820 (date of application: Feb. 3, 1994, Idemitsu) describes the preparation of magnesium ethanolate from magnesium and ethanol in the presence of 0.019 to 0.06 gram-atom of halogen per mol of magnesium.
U.S. Pat. No. 5,965,478 (date of application: 13/08/1997, Toho Titanium) describes a magnesium ethanolate having a bulk density of 0.25-0.40 g/ml and a particle diameter of 1 to 100 μm as a component of a Ziegler-Natta catalyst. This is prepared by continuous or batchwise addition of alcohol and magnesium to a reaction mixture which is not defined in more detail. The synthesis takes place at the reflux temperature.
The flowability of the powder is of great importance for the processing and handling of pulverulent substances. During filling, transferring and emptying operations in particular, for example from barrels or other drums, a rapid flowing out of the magnesium alcoholate powder saves time and expenditure. A good flowability of the magnesium alcoholate powder must also be ensured because this class of substance is highly sensitive to air and water. Residues of substance in drums which have not been emptied completely are a high safety risk. Due to the good flowability, there is also a reduced risk of bridge formation when transferring to silos. Pneumatic delivery of the powder is also facilitated.
In the case of all the abovementioned known magnesium alcoholates, nothing is said about the flowability of the magnesium alcoholates formed here. There is therefore the need for a form of magnesium alcoholate powders which is distinguished by a good flowability.
The object of the invention is to prepare spherical particles comprising magnesium alcoholate or mixtures of magnesium alcoholates having a good flowability. These particles can serve, for example, as starting substance (catalyst precursor) for olefin polymerization catalysts.